1. Field of the Invention
The present invention relates to plasma processing and more particularly to an arc suppression system for plasma processing and a method of using thereof.
2. Discussion of the Background
The fabrication of integrated circuits (IC) in the semiconductor industry typically employs plasma to create and assist surface chemistry within a plasma reactor necessary to remove material from and deposit material to a substrate. In general, plasma is formed within the plasma reactor under vacuum conditions by heating electrons to energies sufficient to sustain ionizing collisions with a supplied process gas. Moreover, the heated electrons can have energy sufficient to sustain dissociative collisions and, therefore, a specific set of gases under predetermined conditions (e.g., chamber pressure, gas flow rate, etc.) are chosen to produce a population of charged species and chemically reactive species suitable to the particular process being performed within the chamber (e.g., etching processes where materials are removed from the substrate or deposition processes where materials are added to the substrate). Typically, during plasma processing such as etch applications, it is likely that electric charge will accumulate across the substrate surface. However, it is possible that the substrate charging can be spatially non-homogeneous across the substrate surface. The non-homogeneous charging of the substrate surface has been observed to arise due to a spatially non-homogeneous plasma overlying and in contact with the substrate surface. The plasma non-homogeneity can be attributed to, for example, non-uniform plasma generation or loss resulting in a non-uniform plasma density, or a non-uniform plasma sheath overlying the substrate surface associated with the plasma reactor structure surrounding the substrate resulting in a non-uniform ion energy (for ions striking the substrate surface). As a consequence of these non-homogeneities, the risk of lateral arcing across the substrate is greatly enhanced. Substrate arcing must be avoided entirely in order to preserve acceptable device yield.